Advance spring
I wish I can get more of them springs. Here pics always help on advances. All it does is adjust the rate of advance by how much it advances by vacuum not total amount of advance. To make it easy say the arm has 10 stamped on it that is the max amount of distributor degrees you can achieve. Say you want that at 51nhg then crank the screw clockwise most of the way. You want it to come in at 10 inhg counter clockwise the screw untill the result is achieved. now to lock it out USUALLY just turn it all the way counte clockwise and it wil compress the rate spring al the way down in effect locking it out. Hope it helps.
I wish I can get more of them springs. Here pics always help on advances. All it does is adjust the rate of advance by how much it advances by vacuum not total amount of advance. To make it easy say the arm has 10 stamped on it that is the max amount of distributor degrees you can achieve. Say you want that at 51nhg then crank the screw clockwise most of the way. You want it to come in at 10 inhg counter clockwise the screw untill the result is achieved. now to lock it out USUALLY just turn it all the way counte clockwise and it wil compress the rate spring al the way down in effect locking it out. Hope it helps.